Some cells in cat and monkey visual cortex show strong preferences for the direction of stimulus motion. Primary visual cortex is the first stage in the geniculocortical visual pathway where direction selectivity is encountered, so the mechanisms underlying direction selectivity must be found there. This project is a detailed, quantitative receptive-field mapping study of direction-selective cells in macaque V1. These studies will establish the spatiotemporal pattern(s) of excitatory and inhibitory ON and OFF inputs to directional cells. Maps will be generated to look at interactions across directional cells' receptive fields, to find out how inputs from different parts of the receptive field combine spatially and temporally to result in directionality. The data will be analyzed to ask which neuronal models could account for this kind of specificity. Direction selectivity is a fundamental property of visual systems in general. In many other sensory and motor systems various kinds of sequence-dependent specificities have been observed. This study offers the potential to understand the underlying mechanism of one such sequence-specific selectivity. Though this is a basic-science level project, understanding this one kind of temporal information processing may shed light on diseases that are thought to involve defects in temporal processing, such as dyslexia and schizophrenia.